Bore hole perforating apparatus



y 9, 1962 H. D. OWEN 3,036,521

BORE HOLE PERFORATING APPARATUS Filed July 28, 1958 INVENTOR.

HARROL D D. OWE/V ATTORNEY atent fifties Patented May 2%, T362 3,036,521 BORE HGLE PERFURATHNG APPARATUS Harrold 1). Gwen, Fort Worth, Tex, assignor to Go Gil Well Services, Inc, Fort Worth, Tex. Filed July 28, 1958, Ser. No. 751,3ti8 6 :Claims. (Cl. 102-20} My invention relates to bore hole perforating apparatus, and more particularly to perforating apparatus of the expendable jet, or shaped charge type.

When perforating a bore hole, it is usually desirable to utilize a plurality of gun units, or shaped charges, for each perforating operation, so that a plurality of perforations are made in the hole. When expendable type gun units are used, it is common practice to link a plurality.

of them together to make a series or chain of gun units, with groups of gun units facing in different radial directions.

When an expendable type jet gun assembly is fixed in a bore hole it is important that the assembly should be disintegrated to the greatest possible extent in order to minimize the problem of debris or junk resulting from incomplete disintegration of the assembly. Expendable jet gun assemblies of the prior art of which I am aware have not provided a satisfactory solution for this problem. Further, such prior art expendable jet gun assemblies leave considerable room for improvements from the standpoints of effectiveness, dependability, and economy of manufacture.

Accordingly, the general object of my invention is to provide improved expendable type jet gun units and assemblies.

Another object of my invention is to provide expendable type jet gun units and assemblies wherein the problem of debris and junk resulting from their use is minimized.

These and other objects are effected by my invention as will be apparent from the following description, taken in accordance with the accompanying drawings, forming a part of this application, in which:

FIG. 1 is a perspective View showing an expendable type jet gun assembly in accordance with a preferred embodiment of the invention;

FIG. 2 is an enlarged fragmentary section view showing details of the structure between adjacent shaped charges of the assembly of FIG. 1;

FIG. 3 is a transverse section view taken at lines 3-3 of FIG. 2;

FIG. 4 is a fragmentary perspective view, partially exploded, showing details of a primer cord slot and clip;

FIG. 5 is a fragmentary perspective view, partially in section, showing a primer cord and clip in place on a gun unit;

FIG. 6 is a fragmentary perspective view, partially exploded, showing an alternative primer cord arrangement; and

FIG. 7 is a perspective view showing a separator link.

Referring now to the drawings, each gun unit comprises a gun body 11, a gun body closure cap 13, a male coupling link 15, and a female coupling link 17. The gun body 11 has the shape of a short cylinder 19, closed at one end by an integral frustro-conical end wall 21, and having a portion of reduced outside diameter at the other end forming a flange 23 for receiving the closure cap 13. Integral with the gun body end wall 21 and coaxial with the gun body cylindrical portion 19, is an outwardly extending short cylindrical projection 2d. This cylindrical projection 25 is provided with a transverse slot 27 substantially as deep as the projection length. Each side wall of the slot is provided with a shallow channel 29 which is centrally disposed in the respective slot side wall and extends in a direction transverse with respect to the slot 27, and of depth substantially the same as the slot depth. The projection 25 with its slot 27 and channels 29, is designed to receive primer cord 31 and a primer cord retainer clip 33, as will be hereinafter more fully described. The gun body closure cap 13 has a short cylindrical side wall 35 integral with a convex dish-shaped end wall 37. The internal diameter of the sidewall 35 is substantially the same as the outer diameter of the gun body flange 23. The internal length of the cap cylindrical portion '35 is substantially the same as the length of the gun body flange 2'3. The interiors of the gun body 11 and its closure cap 13 are suitably contoured to receive a conventional shaped charge 39 and shaped charge liner 4d. The closure cap 13 is designed to make a pressed fit on the gun body 11, with a gasket 43 disposed at the base of the gun body flange 23 to form a seal (see FIG. 2).

As hereinbefore mentioned, each gun body is provided with a male coupling link 15 and a female coupling link 17. The male coupling link 15 is a cylinder of diameter slightly less than the length of the gun body cylindrical portion 19. The female coupling link 17 is made up of a first cylindrical portion 45 having the same diameter as that of the male link 15, and a second cylindrical portion 47 integral with the first and having a diameter greater than that of the male link and having a. central bore 49 of diameter substantially equal to that of the male link 15. The male and female links are formed integral with the gun body 11 and are centered on opposite sides of the gun body cylindrical portion 19 so as to be coaxial, and extending in a direction transverse with respect to the gun body central axis and also parallel to the primer cord receptacle slot 27. The male connector link 15 is provided with a central bore 51 which extends over its entire length and part way through the gun body cylindrical pogtion 19. The first cylindrical portion 45 of the female link 17 is provided with a central bore 53 having diameter the same as that of the bore 51. of the male link 15, and extending part way through the gun body cylindrical portion 19'.

When a plurality of gun units 11 are assembled, the end portion of the male link 15 of one gun unit nests in the bore 49 of the enlarged cylindrical portion 47 of the female link 17 of the adjacent gun unit, as shown by FIG. 2. Each pair of connector links are secured in the assembled position by a pin 55 which is passed through an opening 57 which extends through the links transversely thereof and is centered approximately on a line tangent to the male link outer surface. Between adjacent assembled gun units is a cylindrical cavity 59 formed by the bore of the male link 15 and the bore of the first cylindrical section 45 of the female link 17, which cavity extends from a point part way in the cylindrical portion 19 of one gun body to a point part way into the cylindrical portion 1? of the adjacent gun body. The cylindrical cavity 59 just mentioned is for the purpose of receiving an explosive capsule 61. The explosive capsule 61 (see FIG. 2) is a thin-walled cylindrical container filled with suitable explosive material 63, and sized to fit in said cavity.

In an assembly of gun units 11, the primer cord 31 extends the entire length of the assembly and to a detonator device (not shown). The primer cord 31 is retained in the slot 27 of each gun unit ill by means or" a primer cord retainer clip 33. The clip 33 is generally U shaped in cross-section with a flange portion es extending outwardly at each free end of the U. The clip 33 is made of resilient spring material and dimensioned so that the outwardly extending flanges 6S fit into the receptacle channels 29. The clip 33 is formed to be spread wider than the distance between the channels 29, so that the flange portions 65 will grip the channel walls when the clip is in place.

The explosive capsule e1 normally will have a detonator sensitive portion at one end, and in assembly, that end will be placed adjacent the gun unit 11 which is to be fired first. Preferably, the gun units of an assembly in a bore hole will be fired successively from bottom to top. Thus, the firing of the lowest gun unit will detonate the explosive capsule in the connector link just above it, then the firing of the next lowest gun unit will detonate the explosive capsule in the connector link just above it, and so on. The gun bodies 11, caps "13, and connector links 15, 17 are all made of frangible material so as to achieve a maximum degree of disintegration. The fact that the connector links are made integral with the gun bodies means that less material is required, and consequently, less potential debris, or junk; and also makes possible a greater degree of disintegration. The shaped charge in the gun body 11 assures disintegration of the gun body and cap 13, and the explosive capsule 61 assures disintegration of the connector links 15, 17 and pin 55, while the primer cord 31 disintegrates itself, so there is nothing further to be disintegrated.

The assemblies of gun units may be made up so as to fire various numbers of gun units per unit length of bore hole. The assembly shown in FIG. 1 is made to fire four gun units per foot of bore hole. If it is desired to fire only two gun units per foot of bore hole, then separator links 75 like that shown in FIG. 7 are substituted for alternate gun units. The separator link 75 is the same length as a gun unit, and has a female end portion 77 and a male end portion 79, substantially identical to the female and male links 17, 15 of a gun unit, The separator link 75 has a central bore 81 of diameter equal to that of the male link of a gun unit, and has a pin hole 83 at its female end portion and a pin groove 85 at its male end portion. When the separator link is used, the length of the explosive capsule is made such as to extend the entire distance between adjacent charges. If desired, a length of primer cord, properly sealed at each end and sensitized, may be used as the explosive capsule.

If desired, the sensitive portion of the explosive capsule may be in its side. In this case (see FIG. 6) a notch 67 is made in the connector link adjacent the capsule sensitive portion, and the primer cord 31 is laid in the notch and held in place by a clip 71 having rounded sides 69 to fit the link outer contour and a channel portion 73 which bears on the primer cord. It is understood that the bore hole perforating referred to herein includes perforating of bore hole side walls, or well casing, or both.

The foregoing disclosure and the showings made in the drawings are merely illustrative of the principles of my invention, and are not to be interpreted in a limiting sense.

I claim:

1. An expendable jet gun assembly for use in bore hole perforating operations, comprising a plurality of gun bodies each carrying a shaped charge and having a longitudinal axis coaxial with that of the shaped charge, a tubular male link and a tubular female link made integral with each said gun body and extending coaxially in opposite directions transversely of said body, means for locking a male link of one gun body to the female link of an adjacent gun body, with each joined male and female link defining a closed elongated cavity having end walls in detonating communication with respective adjacent shaped charges, and a sealed capsule type explosive charge in each said cavity, said gun body and links being made of frangible material.

2. An expendable jet gun unit for use in core hole perforating operations, comprising a gun body carrying a 10 shaped charge and having a cylindrical outer surface portion and a longitudinal axis coaxial with that of the shaped charge, tubular male and female coupling links extending coaxially in opposite directions transversely of said gun body, said coupling link being formed integral with said cylindrical outer surface portion, said male coupling link having a substantially uniform transverse cross-section and a substantially smooth exterior surface and a central bore extending over its length and having an end wall in detonating communication with said shaped charge, said female coupling link having a first portion adjacent said gun body like said male link and a second portion of enlarged cross-section integral with said first portion and extending outwardly therefrom, said second portion having a substantially smooth central bore adapted for receiving a male link, said gun body and said links being made of frangible material.

3. An expendable jet gun unit for use in bore hole perforating operations, comprising a gun body adapted for receiving a shaped charge and having a rear end surface,

a cylindrical projection extending outwardly from said surface and coaxial with the gun body central axis, a transverse slot in said projection extending substantially to said gun body end surface, said slot having opposing side walls, a channel centrally disposed in each slot sidewall and extending transversely of said slot and of depth substantially equal to the slot depth, a generally V shaped primer cord retainer clip having a flange portion extending outwardly at each free end of the V, said clip being made of spring steel, with the flanges dimensioned to fit in said channels.

4. An expendable jet gun assembly for use in bore hole perforating operations, comprising a plurality of gun bodies each carrying a shaped charge and having a longitudinal axis coaxial with that of said shaped charge,

a tubular male link and a tubular female link made integral with each gun body and extending coaxially in opposite directions transversely of said body, means for locking a male link of one gun body to the female link of an adjacent gun body, with each joined male and female link defining a closed elongated cavity, a sealed capsule type explosive charge in each said cavity, a length of primer cord extending longitudinally of said assembly, a groove extending part way into the sidewall of one of said links and adapted for receiving a portion of said primer cord, and means for holding said primer cord in said groove, said gun body and said links being made of frangible material.

5. An expendable jet gun assembly for use in bore hole perforating operations, comprising a plurality of gun bodies each carrying a shaped charge and having a longitudinal axis coaxial with that of said shaped charge, a tubular male link and a tubular female link made integral with each said gun body and extending coaxially in opposite directions transversely of said body, one or more tubular separator links interposed between adjacent gun bodies, means for locking respective male and female link portions, with each group of joined links defining a closed elongated cavity having end walls in detonating communication with respective adjacent shaped charges,

and a sealed capsule type explosive charge in each said cavity, said gun body and links being made of frangible material.

6. An expendable jet gun assembly for use in bore hole perforating operations comprising a plurality of gun bodies each adapted for carrying a shaped charge, coupling links between adjacent gun bodies, each pair of said links comprising a cylindrical male portion mating with a cylindn'cal female portion, each with said pair of coupling links being provided with an opening having a central axis substantially tangent to the outer surface of the male link, and a pin received in said opening for locking said links in mated relation.

2,708,408 Sweetman May 17, 1955 6 Lebourg Oct. 16, 1956 Long July 16, 1957 Cecil et al. Ian. 14, 1958 Udry May 6, 1958 Owen June 9, 1959 FOREIGN PATENTS France Jan. 7, 1953 

